Most homes have at least one wall mounted thermostat for automatically regulating the indoor temperature. The thermostat controls the home's furnace and sometimes is also used to control a central air conditioning unit. Within the thermostat is a temperature sensor which actuates an electrical switch at a user determined temperature. To adjust the temperature set point(s) at which the controlled appliance is turned on and off, the thermostat will normally include a dial type adjuster located on its front face or on one of its side edges.
For the most efficient sensing of the indoor temperature, the thermostat must be mounted in a location where it will sense the true room temperature and at the same time be unaffected by the outdoor temperature. This is normally accomplished by mounting the thermostat to one of the home's interior walls in a location that is spaced from any existing ducts, heating units or entryways.
A problem arises when the location that provides the thermostat with maximum effectiveness places it in an area where it is poorly illuminated. For example, a thermostat will often be mounted on a wall of an interior hallway. Most hallways are poorly lit since they are considered to be areas where reading or similar light intensive activities will not be performed. When the homeowner needs to adjust the thermostat, he or she finds that the poor lighting makes the numbers on the thermostat extremely hard to see. Even when the thermostat is located in a well lit room, the thermostat's numbers or controller can be hard to see if they are in a shadow caused by the thermostat structure itself, the design of the room, or placement of nearby room furniture. Poorly lit thermostats are the norm in mobile homes and many older homes.
There are a number of solutions to this problem that are available to the homeowner. The thermostat can be moved to a location where there is more available light. However, this can diminish the accuracy or effectiveness of the thermostat and require the rerouting of the wiring linking the thermostat to the controlled appliance. A second solution is to use a thermostat that includes a built-in light source. This solution requires a new, more expensive thermostat to be purchased and also, the installation of additional wiring to provide power for the light. A third solution is for the homeowner to use a flashlight whenever he or she needs to adjust the thermostat. This latter solution, while effective, is extremely inconvenient.
Therefore, there is a need for a device that can conveniently illuminate a standard thermostat no matter where the thermostat is located.